DPCH multiplexing apparatus and method for outer loop power control in a W-CDMA communication system

ABSTRACT

Disclosed is a method for transmitting a dedicated physical data channel signal over a dedicated physical data channel in the absence of transmission data to be transmitted over the dedicated physical data channel in order to properly maintain a target SIR (Signal-to-Interference Ratio) when there exists new transmission data after the absence of the transmission data in a CDMA (Code Division Multiple Access) mobile communication system. The method comprises generating a dummy bit generation request signal in the absence of the transmission data; and upon receipt of the dummy bit generation request signal, generating a dummy bit stream, and transmitting a dedicated physical data channel signal created by attaching the CRC bit stream to the dummy bit stream.

PRIORITY

This application claims priority to an application entitled “DPCHMultiplexing Apparatus and Method for Outer Loop Power Control in aW-CDMA Communication System” filed in the Korean Industrial PropertyOffice on Feb. 19, 2001 and assigned Serial No. 2001-10172, anapplication entitled “DPCH Multiplexing Apparatus and Method for OuterLoop Power Control in a W-CDMA Communication System” filed in the KoreanIndustrial Property Office on Feb. 20, 2001 and assigned Serial No.2001-10951, an application entitled “DPCH Multiplexing Apparatus andMethod for Outer Loop Power Control in a W-CDMA Communication System”filed in the Korean Industrial Property Office on Feb. 22, 2001 andassigned Serial No. 2001-9082, an application entitled “DPCHMultiplexing Apparatus and Method for Outer Loop Power Control in aW-CDMA Communication System” filed in the Korean Industrial PropertyOffice on May 9, 2001 and assigned Serial No. 2001-25208, the contentsof all of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a CDMA (Code DivisionMultiple Access) mobile communication system, and in particular, to aDPCH (Dedicated Physical Channel) multiplexing apparatus and method forperforming outer loop power control by properly maintaining a target SIR(Signal-to-Interference Ratio).

2. Description of the Related Art

In general, a channel structure of a UMTS (Universal Mobile TerrestrialSystem) CDMA mobile communication system is classified into a physicalchannel, a transport channel and a logical channel. The physical channelis divided into a downlink physical channel and an uplink physicalchannel according to its data transmission direction. Further, thedownlink physical channel is divided into a physical downlink sharedchannel (PDSCH) and a downlink dedicated physical channel (DPCH), whichwill be described with reference to FIG. 1.

FIG. 1 illustrates a structure of a downlink dedicated physical channelin a mobile communication system. Referring to FIG. 1, each frame of thedownlink dedicated physical channel is comprised of 15 slotsSlot#0-Slot#14. Each slot is comprised of dedicated physical datachannels (DPDCHs) for transmitting upper layer data from a Node B to aUE (User Equipment), and dedicated physical control channels (DPCCHs)for transmitting a physical layer control signal. The dedicated physicalcontrol channel DPCCH is comprised of a TPC (Transport Power Control)symbol for controlling transmission power of the UE, a TFCI (TransportFormat Combination Indicator) symbol, and a pilot symbol. As illustratedin FIG. 1, each of the slots Slot#1-Slot#14 constituting one frame ofthe downlink dedicated physical channel is comprised of 2560 chips. InFIG. 1, a first data symbol Data1 and a second data symbol Data2represent upper layer data transmitted from the Node B to the UE overthe dedicated physical data channel DPDCH, and the TPC symbol representsinformation for controlling transmission power of the UE by the Node B.Further, the TFCI symbol indicates a transport format combination (TFC)used for a downlink channel transmitted for a current one frame (=10ms). Finally, the pilot symbol represents a criterion for controllingtransmission power of the dedicated physical channel by the UE. Here,information included in the TFCI can be classified into a dynamic partand a semi-static part. The dynamic part includes TBS (Transport BlockSize) information and TBSS (Transport Block Set Size) information. Thesemi-static part includes TTI (Transmission Time Interval) information,channel coding scheme information, coding rate information, static ratematching information, and CRC (Cyclic Redundancy Check) sizeinformation. Therefore, the TFCI indicates the number of transportblocks (TB) in a channel transmitted for one frame, and assigns uniquenumbers to TPCs used in each of the transport blocks.

FIG. 2 illustrates a structure of an uplink dedicated physical channelin a mobile communication system. Referring to FIG. 2, like the downlinkdedicated physical channel, the uplink dedicated physical channel iscomprised of 15 slots Slot#1-Slot#14. The uplink dedicated physicalchannel has an uplink dedicated physical data channel (DPDCH) and anuplink dedicated physical control channel (DPCCH). Each of the slotsSlot#0-Slot#14 constituting one frame of the uplink dedicated physicaldata channel DPDCH transmits upper layer data from the UE to the Node B.

Meanwhile, each of the slots Slot#0-Slot#14, which constitutes one frameof the uplink dedicated physical control channel is comprised of (i) apilot symbol used as a channel estimation signal when demodulating datatransmitted from the UE to the Node B, (ii) a TFCI symbol indicating atransport format combination (TFC) of channels transmitted for a currentframe, (iii) an FBI (FeedBack Information) symbol for transmittingfeedback information when transmission diversity is used, and (iv) a TPCsymbol for controlling transmission power of the downlink channels.

Transmission power of the downlink/uplink dedicated physical channelsshown in FIGS. 1 and 2 is controlled by a high-speed power controlmethod such as a closed-loop power control method or an outer loop powercontrol method. Herein, the outer loop power control will be described.

The outer loop power control method compares a target SIR required inthe high-speed power control method with an actual SIR of the channel,for both the downlink channel and the uplink channel, and controls thetransmission power by resetting a threshold for the closed-loop powercontrol based on the comparison result between the target SIR and theactual SIR. In general, it is important for the power control method tomaintain a bit error rate (BER) or a block error rate (BLER) in order tosatisfy required communication performance. The outer loop power controlmethod maintains the BER or the BLER at a required level by continuouslyresetting a threshold for maintaining the BER or the BLER. The UE andthe Node B may measure the BER or the BLER through CRC error detectionby analyzing CRC bits included in the received dedicated physical datachannel.

FIG. 5 illustrates a structure of a physical downlink shared channel(PDSCH) in a mobile communication system. Referring to FIG. 5, a 10ms-frame of the physical downlink shared channel is comprised of 15slots Slot#0-Slot#14. Since the UMTS system has a chip rate of 3.84Mcps, each of the slots is comprised of 2560 chips.

The physical downlink shared channel transmits upper layer data from theNode B to the UE in association with the dedicated physical channel, forpower control and transport format combination indication. The physicaldownlink shared channel is shared by a plurality of UEs on a timedivision basis to efficiently transmit a large amount of packet data tothe UEs. In order for the UE to use the physical downlink sharedchannel, separate dedicated physical channels between the UE and theNode B, (namely, the downlink dedicated physical channel and the uplinkdedicated physical channel associated (or interlocked) with the physicaldownlink shared channel) should be maintained. Therefore, in order forthe UE to use the physical downlink shared channel, it should separatelyestablish the downlink and uplink dedicated physical channels. Forexample, if N UEs use the physical downlink shared channel, N downlinkand N uplink dedicated physical channels (i.e., one such dedicatedchannel to each UE) are established so that the N UEs share the physicaldownlink shared channel on a time division basis. Meanwhile, thephysical downlink shared channel is a physically established channel soas to transmit a large amount of packet data, while the dedicatedphysical channel is physically established to transmit a relativelysmall amount of control data and retransmission-related data, comparedwith the physical downlink shared channel. A detailed description ofthis will be made herein below.

A TFCI bit TFCI_(DPCH) transmitted over the dedicated downlink physicalchannel has information indicating a transport format of the physicaldownlink shared channel. Therefore, the downlink TFCI indicates a UE towhich packet data was transmitted over the physical downlink sharedchannel after a lapse of a predetermined time from a given time point.The UE can recognize whether there is physical downlink shared channeldata to receive, by continuously analyzing the downlink dedicatedphysical channel received. Therefore, when the TFCI received by the UEindicates that there exists data to receive in the physical downlinkshared channel of the next frame, the UE receives the data transmittedby the Node B by demodulating and decoding a signal received over thephysical downlink shared channel at the next frame. During the datatransmission over the dedicated physical channel, transmission power iscontrolled using the outer loop power control, a description of whichwill be separately made for normal transmission and gated transmission.

When the uplink or downlink channel has no transport channel data duringnormal transmission, i.e., normal data transmission, CRC bits aretransmitted over the dedicated physical channel for the outer loop powercontrol. However, if only the CRC bits are transmitted or repeated forthe outer loop power control while there is no transport channel data, acombining gain will occur at the receiver, causing a decrease in atarget SIR. Therefore, when there is transport channel data generatedlater, the BLER becomes high until the target SIR is recovered, becauseof the decrease in the target SIR due to transmission of only the CRCbits during non-existence of the transport channel data.

In addition, even when the outer loop power control is applied to thegated transmission, in order to perform outer loop power control whilegating a dedicated physical control channel during data communicationwhere a dedicated channel (DCH) is interlocked with a downlink sharedchannel (DSCH), it is necessary to measure the BER or BLER through CRCerror detection. A detailed description of this will be made hereinbelow.

Herein, a state where the downlink shared channel and the dedicatedchannel are established will be defined as a “DSCH/DCH state”. In theDSCH/DCH state, a UE in data communication should transmit/receive adownlink dedicated channel signal and an uplink dedicated channel signalinterlocked with the downlink shared channel, in order to maintain aproper channel state through power control for a waiting time.Continuously transmitting/receiving the downlink and uplink dedicatedchannel signals in order to maintain the channels wastes battery powerof the UE and increases interference to the downlink and the uplink,thus limiting the number of UEs that can share the downlink sharedchannel.

To solve this problem, the UMTS channel scheme performs DPCCH gating forefficient radio channel management by optionally reducing the number ofslot signals (15 slots/frame) transmitted for every 10 ms-frame over thededicated physical control channel in a state where the dedicatedphysical data channel has no information data (including CRC bits andtail bits). That is, since that the dedicated physical control channelis subject to gating means that there is no user data transmitted overthe dedicated physical data channel, a length of the user data becomeszero (0). A start and end of the DPCCH (Dedicated Physical ControlChannel) gating operation can be performed through either a controlmessage from an upper layer, i.e., a Layer 3, or a TFCI bit. As aresult, it is possible to secure efficient utilization of radioresources and reduce battery consumption by the UE, by reducing anamount of radio channel resources required in maintaining the dedicatedphysical channel for the period where no user data is transmitted overthe physical channel due to the DPCCH gating operation.

In the DPCCH gating mode, there is no user data (including CRC bits andtail bits), so data transmission over the dedicated physical datachannel is suspended. Therefore, a process for multiplexing the downlinkor uplink dedicated physical data channel is not required. However, inorder to perform outer loop power control even while performing theDPCCH gating, it is necessary to measure the BER or BLER through CRCerror detection. Therefore, even though there is no user data totransmit during the DPCCH gating, the dedicated physical data channelincluding the CRC should be transmitted.

As described above, in the gated transmission mode, only the CRC isrepeatedly transmitted over the dedicated physical data channel, socombining occurs at the receiver, causing a decrease in the target SIR.As a result, when transmitting transport channel data after the end ofthe DPCCH gating, the BLER becomes high until the target SIR isrecovered, because of the decrease in the target SIR due to the DPCCHgating, thus making it difficult to secure reliable outer loop powercontrol.

Specifically, a DPCH (Dedicated Physical Channel) multiplexing methodperforms rate matching using Equation (1) defined in the 3GPP (₃ ^(rd)Generation Partnership Project) standard (see 3GPP TS25.212 V3.4.0:Multiplexing and Channel Coding). $\begin{matrix}{{Z_{0,j} = 0}{{Z_{i,j} = {{\left\lfloor \frac{\left( {\left( {\sum\limits_{m = 1}^{i}{{RM}_{m} \times N_{m,j}}} \right) \times N_{{data},j}} \right.}{\sum\limits_{m = 1}^{i}{{RM}_{m} \times N_{m,j}}} \right\rfloor\quad{for}\quad{all}\quad i} = 1}},\ldots\quad,l}{{{\Delta\quad N_{i,j}} = {{Z_{i,m} - Z_{{i - 1},j} - {N_{i,j}\quad{for}\quad{all}\quad i}} = 1}},\ldots\quad,l}} & {{Equation}\quad(1)}\end{matrix}$

In Equation (1), N_(i,j) for the uplink represents the number of bitsincluded in one radio frame of an i^(th) transport channel of atransport format combination (TFC) j before rate matching and for thedownlink represents a multiple of ⅛, an intermediate parameter used inthe rate matching process. Further, N_(data,j) represents the totalnumber of bits filled in CCTrCH (Coded Composite Transport Channel)included in one radio frame of the transport format combination j,RM_(i) represents a rate matching constant of an i^(th) transportchannel, and Z_(i,j) represents an intermediate rate matching parameter.In addition, for the uplink, ΔN_(i,j) represents a final target value inrate matching. If the ΔN_(i,j) is a positive number, it represents thenumber of bits repeated within one radio frame of the i^(th) transportchannel of the transport format combination j, and if the ΔN_(i,j) is anegative number, it represents the number of punctured bits. However,for the downlink, the ΔN_(i,j) is used as an intermediate parameter, avalue of which is a multiple of ⅛, and l represents the number oftransport channels included in the CCTrCH.

In the uplink channel, since transmission data is subject to ratematching after being segmented in a radio frame unit, the numberΔN_(i,j) of repeated or punctured bits of the radio frames is calculatedin accordance with Equation (1) based on N_(i,j) and N_(data,j), and therate matching is performed in the process disclosed in 3GPP TS25.212.

However, in the downlink channel, since the transmission data is subjectto rate matching in a TTI unit before being segmented in a radio frameunit, the rate matching is performed based on N_(i,l) ^(TTI) unlike inthe uplink channel, and this method is disclosed in 3GPP TS25.212. TheN_(i,l) ^(TTI) is a parameter used only in the downlink, and representsthe number of bits included in one TTI for the case of a transportformat l in the i^(th) transport channel before rate matching. In thecase of the downlink channel, the positions of the transport channels inthe radio frame can be either fixed regardless of the transport formatcombination or varied according to the transport format combination. Theintermediate parameters N_(i,j) and ΔN_(i,j) used in Equation (1) have adifferent calculation method and also have a different rate matchingprocess according to circumstances. In the case of the downlink channel,since N_(data,j) does not depend on j, it is replaced with N_(data,*) inEquation (1).

In the downlink channel, if the transport channels have the fixedpositions, N_(i,j) does not depend upon j. Therefore, it is replacedwith N_(i,*). After N_(i,*) is calculated in accordance with Equation(2) below, ΔN_(i,*) is calculated in accordance with Equation (1) usingthe values of N_(i,*) and the N_(data,*). From the calculated ΔN_(i,*),a rate matching target value ΔN_(i,l) ^(TTI) is calculated in a TTI unitof a transport channel i with a transport format l by the processdefined in 3GPP TS25.212. If the ΔN_(i,l) ^(TTI) is a positive number,it represents the number of bits repeated in each TTI of the transportchannel i with the transport format l. However, if the ΔN_(i,l) _(TTI)is a negative number, it represents the number of punctured bits.$\begin{matrix}{N_{i,*} = {\frac{1}{F_{i}} \times \left( {\max_{l \in {{TFS}{(i)}}}N_{i,l}^{TTl}} \right)}} & {{Equation}\quad(2)}\end{matrix}$

In Equation (2), F_(i) indicates the number of radio frames included inone TTI of the transport channel i, and TFS(i) indicates a set of atransport format index l for the transport channel i.

In the downlink channel, if the transport channels have variablepositions according to the transport format combination, N_(i,j) iscalculated in accordance with Equation (3), and then, ΔN_(i,j) iscalculated in accordance with Equation (1) using the N_(i,j) and theN_(data,*). The rate matching target value ΔN_(i,l) ^(TTI) is calculatedin a TTI unit of the transport channel i with the transport format lbased on the calculated ΔN_(i,j) and the process defined in 3GPPTS25.212. $\begin{matrix}{N_{i,j} = {\frac{1}{F_{i}} \times N_{i,{{TF}_{i}{(j)}}}^{TTI}}} & {{Equation}\quad(3)}\end{matrix}$

In Equation (3), TF_(i)(j) represents a transport format of thetransport channel i for the transport format combination j.

Therefore, if channel coding is performing by transmitting only the CRCand/or the tail bit required in measuring the BER or BLER for outer looppower control in a state where there is no user data, the rate matchingis performed in accordance with Equations (1) to (3) and the processdefined in 3GPP TS25.212, thus the number of bits repeated in ratematching after channel coding is larger than when the transport channeldata and the CRC are transmitted together. Therefore, when the user datais normally transmitted over the dedicated physical data channel afterthe end of the DPCCH gating, the target SIR is set to a relatively lowvalue due to the outer loop power control performed by transmitting onlythe CRC, so that it is not possible to efficiently perform thehigh-speed power control at an initial power control stage. This problemcommonly occurs when performing the outer loop power control bytransmitting only the CRC, regardless of whether the gating is applied.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide anapparatus and method for multiplexing a dedicated physical channel so asto perform reliable outer loop power control in a CDMA communicationsystem.

It is another object of the present invention to provided an apparatusand method for multiplexing a dedicated physical channel so as toperform accurate outer loop power control by transmitting a dedicatedphysical data channel according to a gating rate duringgated-transmission of a dedicated physical control channel in a CDMAcommunication system.

It is further another object of the present invention to provide a DPCH(Dedicated Physical Channel) multiplexing apparatus and method forperforming outer loop power control (OLPC) by accurately measuring anSIR in a gated transmission mode in a CDMA communication system.

It is yet another object of the present invention to provide a DPCHmultiplexing apparatus and method for performing outer loop powercontrol by transmitting a dummy bit along with CRC bits over a dedicatedphysical channel in a CDMA communication system.

It is still another object of the present invention to provide a DPCHmultiplexing apparatus and method for performing outer loop powercontrol by transmitting a proper number of dummy bits, determined basedon a gating rate, along with CRC bits in a gated transmission mode in aCDMA communication system.

To achieve the above and other objects, there is provided an apparatusfor transmitting a dedicated physical data channel signal over adedicated physical data channel in the absence of transmission data tobe transmitted over the dedicated physical data channel in order toproperly maintain a target SIR when there exists new transmission dataafter the absence of the transmission data in a CDMA mobilecommunication system. The apparatus includes a controller for generatinga dummy bit generation request signal in the absence of the transmissiondata; a dummy bit generator for generating a dummy bit stream uponreceipt of the dummy bit generation request signal; a CRC (CyclicRedundancy Check) attachment part for attaching a CRC bit stream to thedummy bit stream; and a channel multiplexing part for mapping a firstbit stream created by attaching the CRC bit stream to the dummy bitstream, to the dedicated physical data channel.

To achieve the above and other objects, the present invention alsocomprises a method for transmitting a dedicated physical data channelsignal over a dedicated physical data channel in the absence oftransmission data to be transmitted over the dedicated physical datachannel in order to properly maintain a target SIR(Signal-to-Interference Ratio) when there exists new transmission dataafter the absence of the transmission data in a CDMA (Code DivisionMultiple Access) mobile communication system. The method comprisesgenerating a dummy bit generation request signal in the absence of thetransmission data; and upon receipt of the dummy bit generation requestsignal, generating a dummy bit stream, and transmitting a dedicatedphysical data channel signal created by attaching the CRC bit stream tothe dummy bit stream.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 illustrates a structure of a downlink dedicated physical channelin a general mobile communication system;

FIG. 2 illustrates a structure of an uplink dedicated physical channelin a general mobile communication system;

FIG. 3 illustrates a method for multiplexing an uplink dedicatedphysical channel for outer loop power control in a W-CDMA communicationsystem according to an embodiment of the present invention;

FIG. 4 illustrates a method for multiplexing a downlink dedicatedphysical channel for outer loop power control in a W-CDMA communicationsystem according to an embodiment of the present invention;

FIG. 5 illustrates a structure of a physical downlink shared channel ina mobile communication system;

FIG. 6 illustrates process for channel-coding an uplink channel havingperformance of 12.2 Kbps used in a W-CDMA communication system accordingto an embodiment of the present invention;

FIG. 7 illustrates a modified uplink channel of FIG. 6 for 1/3 DPCCHgating;

FIG. 8 illustrates a modified uplink channel of FIG. 6 for 1/5 DPCCHgating;

FIG. 9 illustrates a structure of a downlink channel having performanceof 12.2 Kbps used in a W-CDMA communication system according to anembodiment of the present invention;

FIG. 10 illustrates a modified downlink channel of FIG. 9 for 1/3 DPCCHgating;

FIG. 11 illustrates a modified downlink channel of FIG. 9 for 1/5 DPCCHgating;

FIG. 12 illustrates a process for multiplexing the dedicated physicalchannel according to an embodiment of the present invention; and

FIG. 13 illustrates an apparatus for multiplexing a dedicated physicalchannel according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the present invention will be described hereinbelow with reference to the accompanying drawings. In the followingdescription, well-known functions or constructions are not described indetail since they would obscure the invention in unnecessary detail.

FIG. 3 illustrates a scheme for multiplexing an uplink transport channelin a CDMA communication system. Referring to FIG. 3, reference numeral301 represents an uplink transport channel generation block. For thesake of convenience, the uplink transport channel generation block 301will be referred to as an “uplink transport channel chain”. Further,reference numeral 302 represents another uplink transport channelgeneration block. Transmission data input to the uplink transportchannel chain 301 is first provided to a CRC attachment part 303. TheCRC attachment part 303 adds CRC bits for BLER checking to thetransmission data and provides the CRC bit-added transmission data to aTrBk (Transport Block) concatenation/code block segmentation part 304.The TrBk concatenation/code block segmentation part 304 concatenates orsegments the CRC bit-added transmission data in a code block size properfor channel coding, and provides its output to a channel coding part305. The channel coding part 305 channel-codes the signal output fromthe TrBk concatenation/code block segmentation part 304 as that thesignal has a channel error-independent property, and provides its outputto a radio frame equalization part 306 in the form of a bit stream. Theradio frame equalization part 306 equalizes the bit stream output fromthe channel coding part 305 in a 10 ms-radio frame unit, and providesits output to a first interleaving (or primary interleaving) part 307.The first interleaving part 307 interleaves the signal output from theradio frame equalization part 306 according to a predeterminedinterleaving rule, and provides its output to a radio frame segmentationpart 308. Here, the interleaving can be performed in a unit of 10 ms, 20ms, 40 ms and 80 ms, and the interleaving unit becomes TTI (TransmissionTime Interval). When the TTI has a value other than 10 ms, the output ofthe first interleaving part 307 is segmented again to be proper for 10ms by the radio frame segmentation part 308, and then provided to a ratematching part 309. The rate matching part 309 generates a bit streamproper for one radio frame size by puncturing or repeating the signaloutput from the radio frame segmentation part 308, and outputs onetransport channel (TrCH). Therefore, two uplink transport channels arecreated with the outputs of rate matching parts 309 and 310. Of course,an increase in the number of the uplink transport channel chainsincreases the number of the transport channels created. The createdtransport channels TrCHs are provided to a TrCH multiplexing part 311.The TrCH multiplexing part 311 multiplexes a plurality of the transportchannels into one coded composite transport channel CCTrCH, and providesits output to a physical channel segmentation part 312. The physicalchannel segmentation part 312 segments the CCTrCH output from the TrCHmultiplexing part 311 in 10 ms size so that it can be mapped to aphysical channel, and then provides its output to a second interleaving(or secondary interleaving) part 313. The second interleaving part 313interleaves the signal output from the physical channel segmentationpart 312 according to a predetermined interleaving rule, and providesits output to a physical channel mapping part 314. Here, an interleavingunit of the second interleaving part 313 becomes 10 ms, which is equalto a size of one radio frame. Finally, the data segmented andinterleaved by the physical channel segmentation part 312 and the secondinterleaving part 313 is mapped into first and second physical channelsPhCH#1 (316) and PhCH#2 (317) by a physical channel mapping part 314.

FIG. 4 illustrates a scheme for multiplexing a downlink transportchannel in a CDMA communication system. The downlink channelmultiplexing process is very similar to the uplink channel multiplexingprocess, except that a rate matching part 406 is arranged at the nextstage of a channel coding part 405 as shown in FIG. 4. The downlinktransport channel multiplexing scheme further includes a first insertionof DTX (Discontinuous Transmission) part 407 or/and a second insertionof DTX part 412. In addition, reference numeral 401 represents adownlink transport channel generation block. Herein, for the sake ofconvenience, the downlink transport channel generation block 401 will bereferred to as a “downlink transport channel chain”. Reference numeral402 represents another downlink transport channel chain. A detaileddescription of the downlink transport channel chains will be givenherein below.

Downlink transmission data input to the downlink transport channel chain401 is first provided to a CRC attachment part 403. The CRC attachmentpart 403 adds CRC bits for BLER checking to the transmission data andprovides the CRC bit-added transmission data to a TrBkconcatenation/code block segmentation part 404. The TrBkconcatenation/code block segmentation part 404 concatenates or segmentsthe signal output from the CRC attachment part 403 in a code block sizeproper for channel coding, and provides its output to a channel codingpart 405. The channel coding part 405 channel-codes the signal outputfrom the TrBk concatenation/code block segmentation part 404 as that thesignal has a channel error-independent property, and then provides itsoutput to rate matching part 406. The rate matching part 406rate-matches the signals output from the channel coding part 405 andprovides its output to the first insertion of DTX indication part 407.The first insertion of DTX indication part 407 inserts a DTX indicatorindicating a data transmission-off point into the signal output from therate matching part 406, and provides its output to a first interleavingpart 408. The first interleaving part 408 interleaves the signal outputfrom the first insertion of DTX indication part 407 according to apredetermined interleaving rule, and provides its output to a radioframe segmentation part 409. Here, the interleaving can be performed ina unit of 10 ms, 20 ms, 40 ms and 80 ms, and the interleaving unitbecomes TTI. When the TTI has a value other than 10 ms, the output ofthe first interleaving part 408 is segmented again to be proper for 10ms by the radio frame segmentation part 409. Finally, the radio framesegmentation part 409 generates one transport channel. Likewise, thedownlink transport channel chain 402 also generates another transportchannel. Of course, an increase in the number of the downlink transportchannel chains increases the number of the transport channels generated.The generated transport channels TrCHs are provided to a TrCHmultiplexing part 411. The TrCH multiplexing part 411 multiplexes aplurality of the transport channels, and provides its output to a secondinsertion of DTX indication part 412. The second insertion of DTXindication part 412 inserts a second DTX indicator into the signaloutput from the TrCH multiplexing part 411, and provides the DTXindicator-inserted signal to a physical channel segmentation part 413.Here, one CCTrCH 418 is generated by inserting the second DTX indicatoras shown in FIG. 4. The physical channel segmentation part 413 thensegments the generated CCTrCH that it can be mapped to a plurality of 10ms-physical channels, and then provides its output to a secondinterleaving part 414. The second interleaving part 414 interleaves thesignal output from the physical channel segmentation part 413 accordingto a predetermined interleaving rule, and provides its output to aphysical channel mapping part 415. Here, an interleaving unit of thesecond interleaving part 415 becomes 10 ms, which is equal to a size ofone radio frame. Finally, the data segmented and interleaved by thephysical channel segmentation part 413 and the second interleaving part414 is mapped into first and second physical channels PhCH#1 (416) andPhCH#2 (417) by a physical channel mapping part 415, completing thedownlink transport channel multiplexing process.

The uplink and downlink transport channel multiplexing processes ofFIGS. 3 and 4 are performed by a transmitter. An uplink/downlinkreceiver has a symmetrical structure of the transmitter, so adescription of the receiver will not be provided. For example, thereceiver has a channel decoding part, a deinterleaving part, ademultiplexing part and a removal of DTX indication part, in place ofthe channel coding part, the interleaving part, the multiplexing partand the insertion of DTX indication part, respectively.

The present invention defines Equation (4) so as to use Equation (1) forthe uplink TrCH multiplexing part 311 during the DPCCH gating, in orderto resolve the problem that the target SIR is set to a lower valuecompared with the normal transmission, when the outer loop power controlrepeatedly transmits only the CRC bits or the tail bits during the DPCCHgating. $\begin{matrix}{\frac{\Delta\quad N_{i,j}}{N_{i,j}} = {K\quad({constant})}} & {{Equation}\quad(4)}\end{matrix}$

That is, Equation (4) should be satisfied in order to efficientlyperform the outer loop power control by maintaining the target SIRregardless of the DPCCH gating operation.

In order to provide a rate matching method efficient at the gating whilesatisfying Equation (4), the parameters N_(i,j) and N_(data,j) inEquation (1) are newly defined to provide Equation (5), a rate matchingformula available for the uplink DPCCH gating. $\begin{matrix}{{Z_{0,j} = 0}{Z_{i,j}^{gating} = \left\lfloor \frac{\left( {\left( {\sum\limits_{m = 1}^{i}{{RM}_{m} \times N_{m,j}^{gating}}} \right) \times N_{{data},j}^{gating}} \right)}{\sum\limits_{m = 1}^{i}{{RM}_{m} \times N_{m,j}^{gating}}} \right\rfloor}\quad{{{{for}\quad{all}\quad i} = 1},\ldots\quad,l}{{{\Delta\quad N_{i,j}^{gating}} = {{Z_{i,j}^{gating} - Z_{{i - 1},j}^{gating} - {N_{i,j}^{gating}\quad{for}\quad{all}\quad i}} = 1}},\ldots\quad,l}} & {{Equation}\quad(5)}\end{matrix}$

In Equation (5), N_(i,j) ^(gating) depicts the number of bits includedin one radio frame in an i^(th) transport channel of a transport formatcombination j before rate matching during the gating. The N_(i,j)^(gating) represents the number of bits included in one radio frame setup to equally or similarly maintain a transmission power level of thesymbols or bits transmitted before the gating, as well as a transmissionpower level of the CRC bits or the other bits transmitted for the outerloop power control during the gating. The reason for equally orsimilarly maintaining a transmission power level of the symbols or bitstransmitted before the gating and a transmission power level of the CRCbits or the remaining bits transmitted for the outer loop power controlduring the gating is because when the CRC bits or the remaining bits aretransmitted without setting up of the N_(i,j) ^(gating) during thegating, they may be excessively repeated in actual transmission. Theexcessive repetition causes a combining effect at the receiver,resulting in a decrease in the target SIR in actual transmission duringthe gating. Therefore, during normal data transmission over the DPCCHafter the end of the gating, the outer loop power control may have apower control error for an initial period due to the decrease in thetarget SIR. In setting the N_(i,j) ^(gating), if a gating rate is 1/n,then N_(i,j) ^(gating)=└N_(i,j)/n┘ or N_(i,j)^(gating)=└└N_(i,j)×(1/n)┘×R┘×R⁻¹.

The second formula, N_(i,j) ^(gating)=└└N_(i,j)×(1/n)┘×R┘×R⁻¹, forsetting the N_(i,j) ^(gating) is advantageous in that a value of the CRCbits or the remaining bits, set before the channel coding, becomes aninteger. Therefore, although there is no data to be transmitted by newlydefining the N_(i,j) ^(gating), a dedicated physical data channel isgenerated using dummy bits as data bits.

That is, the N_(data,j) ^(gating) represents the total number of bitsfilled in the CCTrCH included in one radio frame of the transport formatcombination j. If the gating rate is 1/n, then N_(data,j)^(gating)=N_(data,j)/n. Further, in Equation (5), RM_(i) represents arate matching constant of an i^(th) transport channel, Z_(i,j) ^(gating)represents an intermediate rate matching parameter, and ΔN_(i,j)^(gating) represents a final rate matching target value used for thegating. If the final target value is a positive number, it representsthe number of bits repeated in one radio frame of the i^(th) transportchannel of the transport format combination j. However, if the finaltarget value is a negative number, it represents the number of bitspunctured in the radio frame. In addition, l represents the number oftransport channels included in the CCTrCH.

Meanwhile, in Equation (3), the existing method divides a value of theparameters N_(i,j) ^(gating) and N_(data,j) ^(gating) by the gatingrate. That is, if the gating rate is 1/n, then N_(i,j)^(gating)=└N_(i,j)/n┘. Hence, Z_(i,j) ^(gating)=└Z_(i,j)/n┘. Likewise,ΔN_(i,j) ^(gating)=└ΔN_(i,j)/n┘. Therefore, from Equation (1) andEquation (5), ΔN_(i,j) ^(gating)/N_(i,j) ^(gating)≈ΔN_(i,j)/N_(i,j),thus satisfying a condition of Equation (4). That is, the change in thetarget SIR is almost negligible, regardless of the use of the DPCCHgating.

Next, as described above, first to fourth embodiments of the presentinvention newly define the N_(i,j) ^(gating) value during the DPCCHgating, and then create a DPDCH (Dedicated Physical Data Channel) usingdummy bits as data bits to match a N_(i,j) ^(gating) length, althoughthere is no actual transmission data. Therefore, it is possible totransmit the CRC bit-added DPDCH without excessive CRC repetition bytransmitting the dummy bits as data bits even during the DPCCH gating.As a result, it is possible to maintain a proper target SIR,contributing to efficient outer loop power control.

First, a transport channel multiplexing method used during the uplinkDPCCH gating according to the first and second embodiment of the presentinvention will be described with reference to FIGS. 6 to 8. Inparticularly, the first embodiment will be described on the assumptionthat the dedicated control channel has a gating rate of 1/3.

FIG. 6 illustrates process for channel-coding an uplink channel havingperformance of 12.2 Kbps used in a W-CDMA communication system, FIG. 7illustrates a modified uplink channel of FIG. 6 for 1/3 DPCCH gating,and FIG. 8 illustrates a modified uplink channel of FIG. 6 for 1/5 DPCCHgating.

First, a process for channel-coding a dedicated traffic channel (DTCH)of uplink logical channel (the logical channel is consisted of DTCH andDCCH) will be described with reference to FIG. 6. For the sake ofconvenience, the steps of channel-coding the DTCH will be represented inthe form of blocks, and a number in each block indicates the number ofbits processed in the block. Referring to FIG. 6, 244-bit informationdata is received in block 601, 16-bit CRC is added to the informationdata in block 603, and then, 8 tail bits are added to the CRC-addedinformation data in block 605. Further, the CRC and tail bit-addedinformation data is subject to 1/3 coding (coding rate R=1/3) in block607, thus generating 804 bits. Herein, the coding is assumed to beconvolutional coding. The convolutional-coded bits are interleaved inblock 609, and then, segmented into two radio frames with a sizeN_(i,j)=402 in blocks 611 and 613. The two radio frames are subject torate matching in blocks 615 and 617, respectively, so that each radioframe generates 490 bits proper for an actual physical channel.

Meanwhile, during the gating operation in the 1/3 DPCCH gating of FIG.7, a proper size of a dummy bit stream is determined on the basis of the402-bit radio frame stored in a buffer just before the gating operation,and then dummy bits are inserted in the information data. Therefore, inblocks 711 and 713 of FIG. 7, the number of the information data bitsbecomes N_(i,j) ^(gating)=└N_(i,j)/n┘≈402/3=132 or N_(i,j)^(gating)=└└N_(i,j)×(1/n)┘×R┘×R⁻¹=└└402/3┘×(1/3)┘×3=132, selectivelyusing the formulas according to the present invention. Here, since theN_(i,j) ^(gating) is a multiple of a reciprocal (3) of the coding rate(1/3), it has the intact value 132. In addition, the N_(data,j)^(gating) has a value of 600/3=200. FIG. 7 illustrates a channel codingscheme, i.e., a channel multiplexing scheme for the 1/3 gating, and alength of the actually transmitted information data bits is calculatedby multiplying N_(i,j) ^(gating) by the number of radio frames per TTI,dividing the multiplication result by a reciprocal of a channel codingrate, and then subtracting the number of tail bits and CRC bits from thedivision result, in reverse order of the channel multiplexing. That is,the length of the actually transmitted information bits becomes 132(N_(i,j) ^(gating))×2(TTI=20 ms)÷3 (reciprocal of the coding rate 1/3)−8(tail bits)−16 (CRC bits)=64 bits. The length of the data bits iscalculated by a controller (not shown), and information data of thecalculated data bit length is provided to the uplink transport channelgeneration block 301 of FIG. 3 and the downlink transport channelgeneration block 401 of FIG. 4 in order to establish the uplink anddownlink transport channels. Since there is no user data actuallytransmitted during the gating, meaningless dummy bits are used for the64-bit data in block 701.

Next, in the case of the DCCH (Dedicated Control Channel), since TTI is40 ms, the N_(i,j) has a value of 90 in block 641 of FIG. 6. Therefore,in block 741 of FIG. 7, the data bit number becomes N_(i,j)^(gating)=└└90/3┘×(1/3)×3┘=30. In this case, the data bit length shouldbe 20 bits, and for this, dummy bits are used as data bits consideringthe gating state where there exists no transmission data.

Next, the second embodiment of the present invention will be describedon the assumption that the dedicated control channel has a gating rateof 1/5. First, the dedicated traffic channel (DTCH) out of two logicalchannels (DTCH and DCCH) will be described with reference to FIG. 6.Referring to FIG. 6, 244-bit information data is received in block 601,16-bit CRC is added to the information data in block 603, and then, 8tail bits are added to the CRC-added information data in block 605. Theoutput data of block 607 is comprised of 804 bits. The 804-bit outputdata is subject to interleaving in block 609, and then, segmented intotwo N_(i,j)=402-bit radio frames in block 611. The 402-bit radio framesare subject to rate matching in blocks 615 and 617, respectively.

Meanwhile, during the gating operation, a proper size of a dummy bitstream is determined on the basis of the 402-bit radio frame stored in abuffer just before the gating operation, and then dummy bits areinserted in the information data. Therefore, in blocks 811 and 813 ofFIG. 8, the number of the information data bits becomes N_(i,j)^(gating)=└N_(i,j)/n┘=└402/5┘=80, using the first formula according tothe present invention. However, since the bit number 80 is not amultiple of the coding rate, the information data is subject topuncturing so that the bit number becomes 78, which is a multiple of areciprocal 3 of the coding rate and is also a downlink integer.Alternatively, the number of the information data bits becomes N_(i,j)^(gating)=└└Ni,j×(1/n)┘×R┘×R⁻¹└└402/5×(1/3)┘3=78, using another formulaaccording to the present invention. Since the N_(i,j) ^(gating) based onthe latter formula is a multiple of a reciprocal 3 of the coding rate,it has the intact value 78. In addition, the N_(i,j) ^(gating) has avalue of 600/5=120. FIG. 8 illustrates a channel multiplexing scheme for1/5 gating, and a length of the actually transmitted information databits is calculated by multiplying N_(i,j) ^(gating) by the number ofradio frames per TTI, dividing the multiplication result by a reciprocalof a channel coding rate, and then subtracting the number of tail bitsand CRC bits from the division result. In this embodiment, the length ofthe actually transmitted information bits becomes 78 (N_(i,j)^(gating))×2 (TTI=20 ms)÷3 (reciprocal of the coding rate 1/3)−8 (tailbits)−16 (CRC bits)=28 bits. The length of the data bits is calculatedby a controller (not shown), and information data of the calculated databit length is provided to the uplink transport channel generation block301 of FIG. 3 and the downlink transport channel generation block 401 ofFIG. 4 in order to establish the uplink and downlink transport channels.Since there is no user data to be transmitted during the gating,meaningless dummy bits are used for the 28-bit data in block 801.

Next, in the case of the DCCH (Dedicated Control Channel), since TTI is40 ms, the N_(i,j) has a value of 90 in block 641. Therefore, in block841 of FIG. 8, the data bit number becomes N_(i,j)^(gating)=└└90/5┘×(1/3)×3┘=18. In this case, the data bit length shouldbe 4 bit, and for this, dummy bits are used as data bits considering thegating state where there exists no transmission data.

A multiplexing method for downlink DPCCH gating according to the thirdand fourth embodiments of the present invention will be described withreference to FIGS. 9 to 11.

In the case of the downlink channel, rate matching is performed in a TTIunit under 3GPP TS25.212 as described in the prior art, so that the ratematching is performed based on N_(i,l) ^(TTI). Therefore, even in thecase of the uplink channel, N_(i,l) ^(TTI,gating) for the downlinkchannel is defined and used in place of the N_(i,l) ^(TTI), as proposedin the present invention. The N_(i,l) ^(TTI,gating) can be construed asthe number of bits included in one TTI of a transport channel i with atransport format l set up to equally or similarly maintain atransmission power level of the symbols or bits transmitted before thegating, as well as a transmission power level of the CRC bits or theother bits transmitted for the outer loop power control during thegating. The reason for equally or similarly maintain a transmissionpower level of the symbols or bits transmitted before the gating and atransmission power level of the CRC bits or the remaining bitstransmitted for the outer loop power control during the gating isbecause when the CRC bits or the remaining bits are transmitted withoutsetting up of the N_(i,l) ^(TTI,gating) during the gating, they may beexcessively repeated in actual transmission. The excessive repetitiondecreases the target SIR in actual transmission during the gating, andthe decrease in the target SIR may cause occurrence of a power controlerror during the outer loop power control after the gating. In settingthe N_(i,l) ^(TTI,gating), if a gating rate is 1/n and a channel codingrate is R, then N_(i,l) ^(TTI,gating)=└N_(i,l) ^(TTI)/n┘ or N_(i,l)^(TTI,gating)=└└N_(i,l) ^(TTI)×(1/n)┘×R┘×R⁻¹.

The second formula, N_(i,l) ^(TTI,gating)=└└N_(i,l)^(TTI)×(1/n)┘×R┘×R⁻¹, for setting the N_(i,l) ^(TTI,gating) isadvantageous in that a value of the CRC bits or the remaining bits, setbefore the channel coding, becomes an integer. Therefore, although thereis no data to be transmitted by newly defining the N_(i,l)^(TTI,gating), a dedicated physical data channel is generated usingdummy bits as data bits.

When the position of the transport channel is fixed regardless of thetransport format combination by using the N_(i,l) ^(TTI,gating) insteadof the N_(i,l) ^(TTI) of Equation (2) or (3), N_(i,*) is calculated inaccordance with Equation (2). However, when the position of thetransport channel is variable, N_(i,j) is calculated in accordance withEquation (3). The downlink rate matching is performed by Equation (5)and a method defined in 3GPP TS25.212, using the N_(i,*) or N_(i,j).However, when the N_(i,*) is used in the rate matching process, theN_(i,*) is substituted in Equation (5) instead of the N_(i,j). In thisdownlink rate matching process, since the total number of bits filled inthe CCTrCH per radio frame is independent of a transport formatcombination j, N_(data,*) ^(gating) is used in place of the N_(data,j)^(gating) in Equation (5). The N_(data,*) ^(gating) represents the totalnumber of the CCTrCH bits filled in one radio frame during the gating.If the gating rate is 1/n, then N_(data,*) ^(gating)=└N_(data,*)×P×1/n┘,where P represents the number of transport channels included in oneradio frame.

As described above, the present invention newly defines the N_(i,l)^(TT,gating) value during the DPCCH gating, and then creates a DPDCH(Dedicated Physical Data Channel) using dummy bits as data bits to matcha N_(i,j) ^(gating) length, although there is no transmission data.Therefore, it is possible to transmit the CRC bit-added DPDCH withoutexcessive CRC repetition even during the DPCCH gating. As a result, itis possible to determine a reliable target SIR, thus contributing toefficient outer loop power control.

FIG. 9 illustrates a structure of a downlink channel having performanceof 12.2 Kbps used in a W-CDMA communication system, and FIG. 10illustrates a modified downlink channel of FIG. 9 for 1/3 DPCCH gating.First, a dedicated traffic channel (DTCH) out of two uplink logicalchannels (DTCH and DCCH) will be described herein below. Referring toFIG. 9, 244-bit information data is received in block 901, 16-bit CRC isadded to the information data in block 903, and then, 8 tail bits areadded to the CRC-added information data in block 905. Further, in block907, N_(i,l) ^(TTI) has a value of 804 and N_(data,*) has a length of420 by channel encoding.

Therefore, in block 1007 of FIG. 10, N_(i,l) ^(TTI,gating)=└└N_(i,l)^(TTI)×(1/n)┘×R┘×R⁻¹=└└804/3┘×(1/3)┘×3=267. Further, N_(data,*)^(gating)=420/3=140, so that the output of a rate matching block 1009 iscomprised of 228 bits. The downlink channel multiplexing scheme for 1/3gating is illustrated in FIG. 10. Therefore, a length of the data bitsshould become 65 bits. The length of the data bits is calculated by acontroller (not shown), and information data of the calculated data bitlength is provided to the uplink transport channel generation block 301of FIG. 3 and the downlink transport channel generation block 401 ofFIG. 4. Since there is no transmission data during the gating,meaningless dummy bits are used for the 65-bit data. Typically, ‘0’ bitsor DTX bits are used for the dummy bits.

Next, in the case of the DCCH (Dedicated Control Channel), the output ofblock 937 in FIG. 9 has a value of N_(i,l) ^(TTI)=360. Therefore, thenumber of output bits of block 1037 in FIG. 10 becomes N_(i,l)^(TTI,gating)=└└N_(i,l) ^(TTI)×(1/n)┘×R┘×R⁻¹=360/3=120. In this case,the data bit length should be 20 bits, and for this, dummy bits are usedas data bits considering the gating state where there exists notransmission data. In block 1039, a rate matching part outputs 104 bits.Therefore, a channel multiplexing scheme for 1/3 gating is illustratedin FIG. 10. A length of the information bits is calculated by acontroller (not shown), and information data of the calculated data bitlength is provided to the uplink transport channel generation block 301of FIG. 3 and the downlink transport channel generation block 401 ofFIG. 4.

A channel multiplexing method for 1/5 DPCCH gating according to thefourth embodiment of the present invention will be described hereinbelow. FIG. 11 illustrates a modified downlink channel of FIG. 9 for 1/5DPCCH gating. First, a dedicated traffic channel (DTCH) out of twouplink logical channels (DTCH and DCCH) will be described herein below.Referring to FIG. 9, 244-bit information data is received in block 901,16-bit CRC is added to the information data in block 903, and then, 8tail bits are added to the CRC-added information data in block 905.Further, in block 907, N_(i,l) ^(TTI) has a value of 804 and N_(data,*)has a length of 420 by channel encoding.

Therefore, in block 1107 of FIG. 11, N_(i,l) ^(TTI,gating)=└└N_(i,l)^(TTI)×(1/n)┘×R┘×R⁻¹=└└804/5┘×(1/3)┘×3=159, and N_(data,*)=/420/5=84.Thus, a rate matching part outputs 136 bits in block 1109. The channelmultiplexing scheme for the 1/5 gating is illustrated in FIG. 11.Therefore, a length of the data bits should become 29 bits. The lengthof the data bits is calculated by a controller (not shown), andinformation data of the calculated data bit length is provided to theuplink transport channel generation block 301 of FIG. 3 and the downlinktransport channel generation block 401 of FIG. 4. Since there is notransmission data during the gating, meaningless dummy bits are used forthe 29-bit data. Typically, ‘0’ bits or DTX bits are used for the dummybits.

Next, in the case of the DCCH (Dedicated Control Channel), N_(i,l)^(TTI)=360 in block 1037 of FIG. 10. Therefore, in block 1137 in FIG.11, N_(i,l) ^(TTI,gating)=└└N_(i,l) ^(TTI)×(1/n)┘×R┘×R⁻¹=360/5=72. Inthis case, the data bit length should be 4 bits, and for this, dummybits are used as data bits considering the gating state where thereexists no transmission data. In block 1139, the rate matching partoutputs 64 bits. Thus, a channel multiplexing scheme for the 1/5 gatingis illustrated in FIG. 11. A length of the information bits iscalculated by a controller (not shown), and information data of thecalculated data bit length is provided to the uplink transport channelgeneration block 301 of FIG. 3 and the downlink transport channelgeneration block 401 of FIG. 4.

Meanwhile, a fifth embodiment of the present invention provides anapparatus and method for transmitting data over a dedicated physicaldata channel, when the uplink channel or the downlink channel isrequired to transmit a dedicated physical channel for outer loop powercontrol, even though there is no transport channel data to transmit. Thefifth embodiment transmits CRC bits and dummy bits over the dedicatedphysical data channel in order to properly maintain the target SIR forthe outer loop power control. This will be described with reference toFIGS. 12 and 13.

FIG. 12 illustrates a process for multiplexing the dedicated physicalchannel according to an embodiment of the present invention. Referringto FIG. 12, a Node B transmits transport channel data and CRC bits overthe dedicated physical data channel in step 1201. If it is determined instep 1203 that there is no more transport channel data to transmit, theNode B transmits dummy bits instead of the transport channel data alongwith the CRC bits, for proper outer loop power control, in step 1205.Thereafter, when there exists transport channel data to transmit in step1207, the Node B normally transmits the transport channel data and theCRC bits over the dedicated physical data channel in step 1201. Here,the dummy bit value may be ‘1’ or ‘0’.

An amount of the dummy bits transmitted during absence of the transportchannel data depends upon how to maintain the target SIR for the outerloop power control during the absence of the transport channel data. Forexample, in order to maintain the same target SIR as when the transportchannel data is transmitted last, the Node B must transmit dummy bits asmuch as the last transmitted transport channel data, thus making itpossible to maintain the same target SIR as when there exists transportchannel data although there exists no transport channel data actuallytransmitted over the dedicated physical data channel.

For example, if 244-bit transport channel data was transmitted over theDTCH every 20 ms-TTI and 100-bit transport channel data was transmittedover the DCCH every 40 ms-TTI as illustrated in FIG. 6, the number ofdummy bits transmitted over the DTCH during absence of the actualtransport channel data should also become 244 bits per 20 ms TTI and thenumber of dummy bits transmitted over the DCCH during absence of theactual transport channel data should also become 100 bits per 40 ms TTI,in order to perform the same outer loop power control as when thereexists actual transport channel data. Unlike this, it is also possibleto previously set the number of the dummy bits to be transmitted alongwith the CRC bits, which are transmitted for the outer loop powercontrol although there is no transport channel data to be actuallytransmitted. During the gating, the number of the dummy bits should bedetermined considering the gating rate.

FIG. 12 has described a process for generating the CRC bits and thedummy bits for the outer loop power control, in order to maintain adedicated physical channel for the outer loop power control althoughthere exists no actual transport channel data. Next, an apparatus forgenerating the CRC bits and the dummy bits for the outer loop powercontrol will be described with reference to FIG. 13.

FIG. 13 illustrates an apparatus for multiplexing a dedicated physicalchannel according to an embodiment of the present invention.Specifically, FIG. 13 illustrates an apparatus for transmitting thedummy bits and the CRC bits for the outer loop power control duringabsence of the transport channel data, as described with reference toFIG. 12.

Referring to FIG. 13, a controller 1307 determines whether there existsfurther transport channel data to transmit, while transmitting thetransport channel data and the CRC bits. Here, whether there exists thetransport channel data is determined by the controller 1307 by checkingwhether there exist input information bits 1305. If it is determinedthat there exist input information bits 1305, the controller 1307provides the input information bits 1305 to a CRC attachment part 1311as in the normal DPCH multiplexing process. The CRC attachment part 1311attaches CRC bits to the information bits 1305 output from thecontroller 1307, and then provides the CRC bit-attached information bits1305 to a channel multiplexing chain 1313. The channel multiplexingchain 1313 then generates transport channel data by performing a chainof channel multiplexing processes, including channel coding,interleaving, radio frame segmentation and rate matching, on the signaloutput from the CRC attachment part 1311.

However, if it is determined that there exist no more information bits1305 to transmit, the controller 1307 generates dummy bits to besubstituted for the information bits 1305, in order to maintain thededicated physical channel for the outer loop power control though thereexists no transport channel data to be actually transmitted. Morespecifically, when it is determined that there exist no information bits1305 to transmit, the controller 1307 transmits a dummy bit generationrequest signal 1309 to a dummy bit generator 1301. Upon receipt of thedummy bit generation request signal 1309 from the controller 1307, thedummy bit generator 1301 generates dummy bits to be substituted for theinformation bits 1305. Here, the dummy bits may be ‘0’ or ‘1’, and thenumber of the dummy bits generated by the dummy bit generator 1301 iscontrolled by the controller 1307. That is, the controller 1307determines a pattern and a length of a dummy bit stream 1303 generatedby the dummy bit generator 1301. The length of the dummy bit stream 1303is set to either the number of data bits of the transport channel lasttransmitted before transmission of the dummy bits as described in FIG.12, or a length preset in the system. Here, the number of data bits ofthe transport channel last transmitted before transmission of the dummybits refers to the number of data bits of the transport channeltransmitted during presence of the transport channel data in the normalDPCH transmission mode, and the number of data bits of the previouslytransmitted transport channel in the gated transmission mode where thereexists no transport channel data to transmit after the end of the normaltransmission mode.

The dummy bit generator 1301 provides the generated dummy bit stream1303 to the CRC attachment part 1311. The CRC attachment part 1311attaches CRC bits to the dummy bit stream 1303 output from the dummy bitgenerator 1301, and then provides the CRC bit-attached dummy bit stream1303 to the channel multiplexing chain 1313. The channel multiplexingchain 1313 then generates transport channel data by performing a chainof channel multiplexing processes, including channel coding,interleaving, radio frame segmentation and rate matching, on the signaloutput from the CRC attachment part 1311.

As described in FIGS. 12 and 13, in order to maintain the dedicatedphysical channel for the outer loop power control although there existsno actual transport channel data, it is possible to prevent a decreasein the target SIR during the outer loop power control by transmittingthe same bit stream as when the transport channel data is actuallytransmitted using the CRC bits. Therefore, it is possible to maintain aconstant outer loop power control gain.

Meanwhile, the present invention provides a secondary interleaver. Asillustrated in both the uplink channel multiplexing scheme of FIG. 3 andthe downlink channel multiplexing scheme of FIG. 4, the secondaryinterleaver (313,413) is arranged at a preceding stage of the physicalchannel mapping part. A general secondary interleaver has performance ofa block interleaver, and operates as follows.

Input bits of the secondary interleaver are defined as u_(p,1),u_(p,2),. . . ,u_(p,U), where p indicates a physical channel number and Uindicates a full length of the bits included in one physical channel.The secondary interleaver defines a matrix having a fixed number ofcolumns C2 (set to 30) and a variable number of rows R2 being dependentupon an amount of the data. The R2 should become a minimum integersatisfying a formula, U≦R2×C2. The input bits u_(p,1),u_(p,2), . . .,u_(p,U) are received in a row, generating an R2×C2 matrix of Equation(6). $\begin{matrix}\begin{bmatrix}y_{p,1} & y_{p,2} & y_{p,3} & \cdots & y_{p,{C2}} \\y_{p,{({{C2} + 1})}} & y_{p,{({{C2} + 2})}} & y_{p,{({{C2} + 3})}} & \cdots & y_{p,{({2 \times {C2}})}} \\\vdots & \vdots & \vdots & \cdots & \vdots \\y_{p,{({{({{R2} - 1})} \times}}} & y_{p,{({{({{R2} - 1})} \times}}} & y_{p,{({{({{R2} - 1})} \times}}} & \cdots & y_{p,{({{R2} \times}}} \\\quad_{{{C2} + 1})} & \quad_{{{C2} + 2})} & \quad_{{{C2} + 3})} & \quad & \quad_{{C2})}\end{bmatrix} & {{Equation}\quad(6)}\end{matrix}$

In the matrix of Equation (6), y_(p,k)=u_(p,k) where k=1,2, . . . ,U. IfU<R2×C2, dummy bits are attached to satisfy R2×C2=U. The matrix shown inEquation (6) is subject to column permutation using Table 1. TABLE 1Column Permuted Form Number of Columns (C2) <P2(0), P2(1), . . .,P2(C2-1)> 30 <0, 20, 10, 5, 15, 25, 3, 13, 23, 8, 18, 28, 1, 11, 21, 6,16, 26, 4, 14, 24, 9, 19, 29, 12, 2, 7, 22, 27, 17>

That is, each column of the matrix is permuted in the form of Table 1,so that 0^(th) column is rearranged in 0^(th) column, 20^(th) column in1^(st) column, 10^(th) column in 2^(nd) column, . . . , generating anoutput matrix of Equation (7). $\begin{matrix}\begin{bmatrix}y_{p,1}^{\prime} & y_{p,{({{R2} + 1})}}^{\prime} & y_{p,{({{2 \times {R2}} + 1})}}^{\prime} & \cdots & y_{p,{({{{({{C2} - 1})} \times {R2}} + 1})}}^{\prime} \\y_{p,2}^{\prime} & y_{p,{({{R2} + 2})}}^{\prime} & y_{p,{({{2 \times {R2}} + 2})}}^{\prime} & \cdots & y_{p,{({{{({{C2} - 1})} \times {R2}} + 2})}}^{\prime} \\\vdots & \vdots & \vdots & \cdots & \vdots \\y_{p,{R2}}^{\prime} & y_{p,{({2 \times {R2}})}}^{\prime} & y_{p,{({3 \times {R2}})}}^{\prime} & \cdots & y_{p,{({{R2} \times {C2}})}}^{\prime}\end{bmatrix} & {{Equation}\quad(7)}\end{matrix}$

The secondary interleaver, i.e., a block interleaver, outputsy′_(p,1),y′_(p,2), . . . ,y′_(p,U) in a row, and deletes the output bitscorresponding to the attached dummy bits, thereby completing thesecondary interleaving operation. The output of the secondaryinterleaver is provided to the physical channel mapping part 314 of FIG.3 or the physical channel mapping part 415 of FIG. 4, and then subjectedto physical channel mapping.

Meanwhile, during the DPCCH gating, the secondary interleaver operatesin a different way. That is, the number of input bits of the secondaryinterleaver becomes less by the gating rate as compared with when thegating is not used, and the output of the secondary interleaver is alsosubjected to gating and then transmitted over only the selected slots.The present invention provides a modified secondary interleaverapplicable to a DPCCH gating mode where the DPCCH gating is used. TABLE2 Slots for Transmitting Downlink DPCCH CFN Gating Rate Pilot TPC TFCICFN mod 1 All slots All slots All slots (RX gating DRX cycle) = 0 (0, 1,. . ., 14) (0, 1, . . ., 14) (0, 1, . . ., 14) 1/3 j × 3 + s(i, j) − 1 j× 3 + s(i, j) All slots (0, 1, . . ., 14) 1/5 j × 5 + s(i, j) − 1 j ×5 + s(i, j) All slots (0, 1, . . ., 14) CFN mod 1 All slots All slotsAll slots (RX gating DRX cycle) ≠ 0 (0, 1, . . ., 14) (0, 1, . . ., 14)(0, 1, . . ., 14) 1/3 j × 3 + s(i, j) − 1 j × 3 + s(i, j) j × 3 + s(i,j) 1/5 j × 5 + s(i, j) − 1 j × 5 + s(i, j) j × 5 + s(i, j)

TABLE 3 Slots for Transmitting Uplink DPCCH Gating Rate (Pilot, TFCI,FBI, TPC) 1 All slots (0, 1, . . ., 14) 1/3 j × 3 + s(i, j) 1/5 j × 5 +s(i, j)

Table 2 shows slots for transmitting downlink DPCCHs according to thegating rates, and Table 3 shows slots for transmitting uplink DPCCHsaccording to the gating rates. In table 2, the DRX (DiscontinuousReception) cycle represents a certain interval where the receiverreceives all signals regardless of the gating. $\begin{matrix}{{{s\left( {i,j} \right)} = \begin{Bmatrix}{{\left( {A_{j} \oplus C_{j}} \right)_{10}\quad{mod}\quad\left( {S - 1} \right)} + 1} & {j = 0} \\{\left( {A_{j} \oplus C_{j}} \right)_{10}\quad{mod}\quad S} & {{j = 1},\ldots\quad,{N - 2}} \\{S - 1} & {j = {N - 1}}\end{Bmatrix}}{{i = 0},1,\ldots\quad,255}} & {{Equation}\quad(8)}\end{matrix}$

In Equation (8), N depicts a reciprocal of the gating rate, S=15/N,A_(j) is defined as shown in Equation (9), i represents CFN (CurrentFrame Number), and C_(i)=i+256*i. $\begin{matrix}{{\left( {a_{18},a_{17},\ldots\quad,a_{0}} \right) = \left( {1,0,0,1,0,1,1,1,0,1,1,0,0,1,0,1,1,0,1} \right)}{{A_{j} = {{\sum\limits_{k = j}^{j + 15}{2^{k - j}a_{k}\quad j}} = 0.}},1,\ldots\quad,{N - 2}}} & {{Equation}\quad(9)}\end{matrix}$

During the DPCCH gating, a format of the slots transmitted over one 10ms-radio frame is determined using Equation 8 and Tables 2 and 3. Thatis, the downlink slots for transmitting Pilot, TPC and TFCI bits can bedetermined using Table 2 according to s(i,j) of Equation (8), and theuplink slots for transmitting all the bits can be determined using Table3. The downlink dedicated physical data channel for the outer loop powercontrol is transmitted over the same slot as that of the TPC, while theuplink dedicated physical data channel for the outer loop power controlis transmitted over the same slots as those of the Pilot, TPC, FBI andTFCI.

Therefore, the secondary interleaver should operate in a different modefrom the existing non-DPCCH gating mode (i.e., normal transmissionmode). An operation of the secondary interleaver for DPCCH gatingaccording to sixth and seventh embodiments of the present invention willbe described herein below.

In the sixth embodiment, the secondary interleaver maps transmissiondata only to several slots, which were selected according to the gatingrate from 15 slots in one radio frame, in a system supporting the gatedtransmission.

During the gating, the number of input bits of the secondary interleaveris decreased by the gating rate as compared with when the gating is notused. Therefore, in order to maintain the size of the matrix shown inEquation (6), it is necessary to attach the dummy bits. In order to mapthe attached dummy bits to the physical channel using the intact matrixof the secondary interleaver applied to the existing non-gating mode, itis necessary to match the input bits of the secondary interleaver sothat the interleaved signal are mapped in the gating slot format definedin Equation (8) and Tables 2 and 3. That is, when a number of a slotcurrently transmitted after being subject to gating is determined,columns corresponding to the transmitted slot is determined fromEquation 7, and then meaningful columns to be transmitted in pre-columnpermutation data are determined from Equation (6). That is, a means ofdeinterleaving is used during the secondary interleaving. In this case,the input bits of the secondary interleaver are applied only to themeaningful columns of Equation 6, and dummy bits are applied to theremaining columns. Therefore, the meaningful data is mapped only to theslots subjected to the gated transmission when mapping the output of thesecondary interleaver to the physical channel in the existing samemethod.

For example, if the gating rate is 1/3 and CFN==0, then S=5 and N=3.Thus, s(0,j) becomes {1,1,0,2,2} under Equation (6). Therefore, based onTable 2, the downlink channel transmits TPC, TFCI and DPDCH over 1^(st),4^(th), 6^(th), 11^(th) and 14^(th) slots, and transmits Pilot over0^(th), 3^(rd), 5^(th), 10^(th) and 13^(th) slots. In order to transmitthe DPDCH over the 1^(st), 4^(th), 6^(th), 11^(th) and 14^(th) slots,the meaningful data, i.e., input bits of the secondary interleaver,should exist in the 2^(nd), 3^(rd), 8^(th), 9^(th), 12^(th), 13^(th),22^(nd), 23^(rd), 28^(th) and 29^(th) columns in the matrix of Equation(7). Therefore, the meaningful data should exist only in the 1^(st),5^(th), 8^(th), 9^(th), 10^(th), 11^(th), 17^(th), 23^(rd), 27^(th) and29^(th) columns in the matrix of Equation (6), through columnpermutation of Table 1.

In addition, although the input bits are applied in a row to thesecondary interleaver 414 of FIG. 4 in the matrix of Equation (6), onlythe 1^(st), 5^(th), 8^(th), 9^(th), 10^(th), 11^(th), 17^(th), 23^(rd),27^(th) and 29^(th) columns are filled with the data bits, while theremaining columns are filled with the dummy bits. After being filledwith the data bits and dummy bits, the secondary interleaver creates thematrix of Equation (7) through column permutation of Table 1, and atotal of 15 slots are mapped in such a manner that two columns aremapped to each slot along the columns of the matrix. As a result, themeaningful data bits are mapped to the 1^(st), 4^(th), 6^(th), 11^(th)and 14^(th) slots, for proper transmission during the gating.

In the second embodiment, the secondary interleaver maps transmissiondata only to several slots, which were selected according to the gatingrate from 15 slots in one radio frame, in a system supporting the gatedtransmission. During the gating, the number of input bits of thesecondary interleaver is decreased by the gating rate as compared withwhen the gating is not used. Therefore, if the number of columns of thematrix shown in Equation (6) is matched to the existing value, thenumber of rows will be decreased according to the gating rate. That is,after the input bits are applied along a row in the existing method, thedummy bits are attached to fill the last column and then the columnpermutation of Table 1 is performed, creating the output matrix ofEquation (7). Likewise, the number of columns becomes smaller accordingto the gating rate as compared with the output matrix for the case ofthe existing normal transmission mode. If elements of the matrix areread in a row and then mapped with only the slots subjected to gatedtransmission, all the meaningful bits input to the secondary interleaverare mapped with only the slots subjected to gated transmission withoutthe dummy bits, thus making it possible to perform efficientinterleaving.

For example, if the gating rate is 1/3 and CFN==0, then S=5 and N=3.Thus, s(0,j) becomes {1,1,0,2,2} under Equation (6). Therefore, based onTable 2, the downlink channel transmits TPC, TFCI and DPDCH over 1^(st),4^(th), 6^(th), 11^(th) and 14^(th) slots, and transmits Pilot over0^(th), 3^(rd), 5^(th), 10^(th) and 13^(th) slots. During the non-gatingmode, if the matrix of Equation (6) is a R2×C2=60×30 matrix in thesecondary interleaving and it is not necessary to attach dummy bits,then an output matrix of Equation (7) also has a size of 60×30, and twocolumns are mapped to each slot along a row. That is, a size of one slotbecomes 120 bits. In this case, for 1/3 gating, the matrix of Equation(6) becomes a 20×30 matrix. That is, a size of the column is reduced bythe gating rate 1/3. The output matrix of Equation (7) created throughcolumn permutation of Table 1 also becomes a 20×30 matrix. In this case,6 columns are mapped to each slot by mapping 5 slots among a total of 15slots. That is, 20×6=120 bits are mapped to one slot, so that the databits are equally transmitted as in the normal transmission mode.

An eighth embodiment of the present invention provides new interleavingfor the gated transmission. The existing interleaving divides the C2value of Equations (4) and (5) by the gating rate. That is, C2=10 for1/3 gating and C2=6 for 1/5 gating. In this embodiment, the matrix ofEquations (6) and (7) is reduced in the number of the columns only, andbecomes the same as when the gating is not used. However, the columnpermutation of Table 1 should be newly defined. 10 columns are permutedfor 1/3 gating, while 6 columns are permuted for 1/5 gating. This isshown in Tables 4 and 5. TABLE 4 Column Permuted Form No of Columns (C2)<P2(0), P2(1), . . ., P2(C2-1)> 10 <0, 5, 3, 8, 1, 6, 4, 9, 2, 7>

TABLE 5 Column Permuted Form No of Columns (C2) <P2(0), P2(1), . . .,P2(C2-1)> 6 <0, 5, 3, 1, 4, 2>

In conclusion, the secondary interleaving is efficiently performed bymapping data bits in two columns to one slot along a row regardless ofthe gating rate in the output matrix of Equation (7).

As described above, when transmitting CRC bits for outer loop powercontrol although there is no transport channel data in the uplink ordownlink channel, the CDMA mobile communication system transmits dummybits along with CRC bits so as to properly maintain a target SIR, thusmaking it possible to perform reliable outer loop power control. Inaddition, the present invention prevents a decrease in the target SIRduring outer loop power control by transmitting the dummy data bits asmany as the number of the transport channel data bits transmitted justbefore a point where there exists no transport channel data, in the casewhere the transport channel data does not exist temporarily even in thenormal DPCH transmission mode, i.e., in the case where it is necessaryto maintain the dedicated physical channel for outer loop power controlalthough there exists no transport channel data to be actuallytransmitted. Thus, the outer loop power control gain is properlymaintained, making it possible to continuously perform the stable outerloop power control even when there exists transport channel data afterthe absence of the transmission channel data.

In addition, the transmitter transmits the dedicated physical datachannel according to the gating rate while transmitting the dedicatedphysical control channel, so that the receiver can receive the dedicatedphysical data channel even during the gating, contributing to accurateouter loop power control.

While the invention has been shown and described with reference to acertain preferred embodiment thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1-3. (canceled)
 4. A method for transmitting a dedicated physical datachannel signal over a dedicated physical data channel in the absence oftransmission data to be transmitted over the dedicated physical datachannel in order to properly maintain a target SIR when there exists newtransmission data after the absence of the transmission data in a CDMAmobile communication system, comprising the steps of: generating a dummybit generation request signal in the absence of the transmission data;upon receipt of the dummy bit generation request signal, generating adummy bit stream, and generating a matrix by sequentially receiving in arow a first bit stream created by attaching a CRC (Cyclic RedundancyCheck) bit stream to the dummy bit stream and dedicated physical datachannel signals to be transmitted over one or more additional dedicatedphysical data channels being different from said dedicated physical datachannel; and performing interleaving to delete bits corresponding to thedummy bit stream by performing column permutation on the matrix, andmapping the interleaved signal to the dedicated physical channel signal.5. The method as claimed in claim 4, wherein the dummy bit stream isequal in bit number to data bits transmitted over the dedicated physicaldata channel when transmission data is present.
 6. The method as claimedin claim 4, wherein the dummy bit stream has a predetermined number ofbits. 7-9. (canceled)
 10. An apparatus for transmitting a dedicatedphysical data channel signal over a dedicated physical data channel inthe absence of transmission data to be transmitted over the dedicatedphysical data channel in order to properly maintain a target SIR whenthere exists new transmission data after the absence of the transmissiondata in a CDMA mobile communication system, comprising: a controller forgenerating a dummy bit generation request signal in the absence of thetransmission data; a dummy bit generator for generating a dummy bitstream upon receipt of the dummy bit generation request signal; a CRCattachment part for attaching a CRC bit stream to the dummy bit stream;and a channel multiplexing part for generating a matrix by sequentiallyreceiving in a row a first bit stream created by the CRC bit stream andthe attached dummy bit stream and other dedicated physical data channelsignals, interleaving to delete bits corresponding to the dummy bitstream by performing column permutation on the matrix, and mapping theinterleaved signal to a dedicated physical data channel.
 11. Theapparatus as claimed in claim 10, wherein the dummy bit stream is equalin bit number to the data bits transmitted over the dedicated physicaldata channel when the transmission data is present.
 12. The apparatus asclaimed in claim 10, wherein the dummy bit stream has a predeterminednumber of bits.